Effects of pre- and postnatal protein malnutrition in hypoxic-ischemic rats

Neonatal hypoxic-ischemic encephalopathy (HI) is a major cause of nervous system damage and neurological morbidity. Perinatal malnutrition affects morphological, biochemical and behavioral aspects of neural development, including pathophysiological cascades of cell death triggered by ischemic events, so modifying resulting brain damage. Female Wistar rats were subjected to protein restriction during pregnancy and lactation (control group: 25% soybean protein; malnourished group: 7%). Seven days after delivery (PND7), their offspring were submitted to unilateral cerebral HI; rats were then tested for sensorimotor (PND7 and PND60) and memory (PND60) functions. Offspring of malnourished mothers showed marked reduction in body weight starting in lactation and persisting during the entire period of observation. There was a greater sensorimotor deficit after HI in malnourished (M) animals, in righting reflex and in home bedding task, indicating an interaction between diet and hypoxia-ischemia. At PND60, HI rats showed impaired performance when compared to controls in training and test sessions of rota-rod task, however there was no effect of malnutrition per se. In the open field, nourished HI (HI-N) presented an increase in crossings number; this effect was not present in HI-M group. Surprisingly, HI-M rats presented a better performance in inhibitory avoidance task and a smaller hemispheric brain damage as compared to HI-N animals. Our data points to a possible metabolic adaptation in hypoxic-ischemic animals receiving protein malnutrition during pregnancy and lactation; apparently we observed a neuroprotective effect of diet, possibly decreasing the brain energy demand, under a hypoxic-ischemic situation.